Multi-fluid thermal energy conversion system

ABSTRACT

Briefly, an engine is provided that has a cavity constructed to enable a working liquid to be vaporized upon contact with a hot liquid. As the working liquid is vaporized, the liquid rapidly expands into a vigorous gas. The ensuing rise in pressure causes a moving member to be moved, thereby converting the explosive rise in pressure within the cavity into useful work. In one embodiment, the engine is a piston engine that allows a hot liquid oil to be injected into a piston cavity. Water is then injected, which immediately flashes into steam as the water hits the hot oil. The steam causes the pressure to dramatically rise in the piston cavity, thereby driving the piston.

BACKGROUND

This application claims priority to U.S. provisional application number 61/728,377, filed Nov. 20, 2012, and entitled “Multi-Fluid Thermal Energy to Mechanical and/or Electrical Work Conversion System,” which is incorporated herein in its entirety.

The field of the present invention is engines, which in one example may be a rotary or a piston engine using thermal mixing as a driving force.

Engines power the modern world, and it is desirable that the engines be as efficient in converting energy into useful work. Most commonly, engines have a cavity where a fossil fuel is placed under pressure and ignited. The controlled explosion is used to move a piston in a reciprocating engine, or a rotor in a rotary engine, thereby converting the explosive energy into a form of work that can be used. However, the fuel-based engine is quite inefficient in making this conversion, and also generates considerable pollution and undesirable gasses. Therefore, there exists a need for a better engine.

SUMMARY

An engine is provided that has a cavity constructed to enable a working liquid to be vaporized upon contact with a hot liquid. As the working liquid is vaporized, the liquid rapidly expands into a vigorous gas. The ensuing rise in pressure causes a moving member to be moved, thereby converting the explosive rise in pressure within the cavity into useful work. In one embodiment, the engine is a piston engine that allows a hot liquid oil to be injected into a piston cavity. Water is then injected, which immediately flashes into steam as the water hits the hot oil. The steam expands and causes the pressure to dramatically rise within the piston cavity, thereby driving the piston.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a piston and cavity for an engine in accordance with the disclosed invention.

FIG. 2 is a side view of a piston and cavity for an engine in accordance with the disclosed invention.

FIG. 3 is a side view of a piston and cavity for an engine in accordance with the disclosed invention.

DETAILED DESCRIPTION

It is well known that many substances can exist in different phase states (solid, liquid or gas) depending on the temperature and pressure of the substance. As a result of these changes in phase ranges, these substances will also give rise to differing partial pressures at a given temperature. When a given mass of substance transitions from the liquid phase to its gas phase, its volume increases by as much as two orders of magnitude, or more. The specific value for this dramatic volumetric change depends upon both the temperature and pressure at which the transition takes place. It also depends upon the overall volume to which the gas can expand into.

Further, if a substances is subjected to a change in pressure, the substance will react differently depending on what phase state it is in. If the substance is in either a solid or liquid form, it will have only a very small volumetric change due to the changed pressure as compared to the volumetric change of a gas subjected to a similar pressure change. For purposes of this disclosure, a first order approximation can be made that a pressure change of less than ten thousand psi on a substance in liquid or solid state will have a negligible volumetric variation such that the change in volume can be assumed to be zero. As such, the pressure seen within all of the substances that are in either the liquid or solid phase will be considered isotropic and mono-valued.

In another aspect of material properties, various substances show different tendencies or capacity to mix or separate. This readiness to mix, or not to mix, is determined by several physical factors. The mixing of various substances, and the speed at which mixing occurs, is dependent upon the specific phase that each of the given substances is in at the time of combination. And the phase of each of the substances directly relates to the temperatures of the substances just prior to mixing. In the range of devices discussed in this disclosure, it is understood that the various substances to be mixed will not be at the same temperature. But under most situations they will be in the liquid phase. Another factor profoundly affecting molecular/atomic intermixing of substances (as distinguished from the interaction of materials through chemical recombination), and which also varies with temperature and pressure, is the inherent molecular/atomic level attractive and/or repulsive forces existing between the various substances.

The embodiments described here have two or more substances can be brought together within a given space or cavity, and a given volume, and that through a purely molecular/atomic mixing process, (as distinguished from chemical combining process, or a thermal transfer process done through a physical barrier) physical work can be generated by the mixing system. The physical work can take either the form of mechanical movement or electrical/magnetic action. A good example of this concept is that of mixing water with oil.

If prior to mixing water with a given volume oil, the water is below its normal boiling point of 100° C., its partial pressure will exist below 101 kPa. Most oils, having a much higher boiling/ flash point than that of water, will have a partial pressure below that of 101 kPa even when heated to temperatures above 100° C. Depending upon the type of oil used, this temperature could be as high as 330° C. As is well known, the mixing of liquid water with an oil heated to above the normal boiling point of water, but still below the oil's boiling/flash point, can, under the proper conditions, lead to an extremely vigorous physical response. If the molar-mass of the water is a small fraction of the overall molar-mass of the oil/water mixture, and if the water is introduced into the oil as small droplets having large surface area and small volume, thermal energy transfer to the water will be very rapid, leading to a vigorous physical change to the water. That then will lead to rapid physical change to the oil, and then the rest of the system.

The ratio of molar mass of the water is preferably in the range of hundreds of times smaller than the molar mass of the oil. For example, a range of 600 to 800 times smaller is most preferred, but it will be appreciated that a wider range can be used depending on the specific requirements of the engine design. As a general goal, it is desired that the ratio of hot liquid and working liquid be such that the when the working liquid has fully expanded, that the liquid oil and the water/steam have about the same volume.

This vigorous physical response of the above mentioned mixing of oil and water can take a number of different forms depending upon the environment it occurs within. If the mixing takes place in an open system, an environment lacking a completely enclosing barrier which would restrict the process of expansion, then the mixing response will be one involving little or no work. In this situation, the substance undergoing a liquid to gas transition will experience a free expansion into its surroundings without imposing any substantial elevated pressure on a rigid component within the system. Without such action, no organized movement against a force will take place.

If the above mixing takes place within a well confined space, a space surrounded by a rigid, adiabatic boundary, and where the initial volume of the confining space matches that of the total volume of the oil and water as liquids, the resulting action can lead to a vigorous physical reaction. The initial response would not be one of a rapid substantial volume change. Rather, it would be one of a rapid pressure rise. In the first best example of this concept, this pressure rise would occur within the injected water as a result of rapid heating. This increased pressure would then be transmitted to the much larger volume of oil. The oil would then transfer it to the confining boundary, causing the whole of the confined system to experience a rise in pressure.

Now if this confining system is designed with rigid parts that are meant to move against a pressure gradient, then the physical response to water's pressure rise can be translated into an organized mass movement against a force, giving rise to mechanical work. As in accordance with the fundamental concepts of thermodynamics, the level of efficiency of this mechanical process is directly related to the degree of increased pressure achieved during the expansion process. i.e. the movement of the above mentioned rigid parts: the greater the pressure during expansion, the greater the efficiency of work.

The maximum pressure within this particular process depends directly upon the equalization temperature of the mixed fluid; assuming that the volume change is very much slower than the rise of temperature within the water during the early stage of mixing. The interplay of three factors establishes what the equalized temperature will be.

The first factor is the specific heat capacities of the various substances being mixed. In the case of water and oil, water's specific heat capacity exceeds most oils by about a factor of four. As a consequence, the effects of water on the temperature equalization process during adiabatic mixing is over four times greater, per molar mass, than that of the oil involved in the mix.

The second factor determining equalized temperature is the temperatures of the various substances just prior to their combining. The final factor that determines the equalization temperature is the ratio of the molar masses of the substances involved in the intermixing process. In the case of a water/oil mixing process, should the molar mass of the liquid water be kept very small compared to the molar mass of the oil, and therefore the effects of the water's higher specific heat capacity and lower temperature are kept to a minimum, the equalization temperature will approximate that of the temperature of the oil.

Under these conditions, the value of the peak pressure in the process can be approximated to that of the saturation pressure of water at the equalization temperature, which is approximately that of the oil temperature prior to mixing.

The following are several specific examples of calculating peak pressure in a given oil/water mixing process in a restricted space. In the first example, assume that the initial temperature of the oil is 260° C. At this temperature, the pressure peak would be approximately 4.69 MPa (680 psi). This value is within the range of peak pressures for a gasoline based internal combustion engine. With oil at 300° C., the pressure climbs to 8.58 MPa (1200 psi); this pressure value matches the peak pressures seen in diesel engines. If the income oil temperature is set to 330° C.—the upper temperature range for synthetics oils-the peak pressure will be in excess of 12.85 MPa (1800 psi).

As seen by these calculations, the peak pressure in the cylinder can be precisely controlled by adjusting the inbound temperature of the oil. The higher the oil temperature, the greater will be the potential efficiency. But as the peak pressure increases, so does the potential for mechanical failure, One of the trade-offs in the devices being discussed here is between maximizing efficiency and minimizing the potentials for mechanical failure.

The basic concept presented is that a system using two or more substances are mixed in such a way that at least one of the substances undergoes a liquid to gas phase change while one or more of the other substances provides the thermal energy required to drive the transition process. That this mixing process occurs within a space with adequate confining boundary that allows for a buildup of pressure that is then directed to act upon one or more rigid structures to accomplish work.

There are four basic configurations that this concept can be made to work under. The first possibility is a piston mechanism which would involve linear-reciprocating motion. The second is a turbine device where the expanding gas/liquid solution translates to a rotary motion of rigid components. The disk-based system similar to that implemented by Nikola Tesla would provide one means of applying this concept in a rotating mechanical system.

The third possibility is a hydraulic, fluid based mechanism. In this later system, as expressed in the first best example of this technology, the oil not only serves as the heat transfer system but also as a long distance mechanical transfer agent, as would be seen in a standard hydraulic system. In this latter approach, energy is not transferred to the hydraulic system by some mechanical pump but by the rise in pressure due to the phase change of one of the mixing fluids, such as the expansion of water. In this arrangement, the induced fluid flow can travel some distance from where the working fluid does its expansion, to a place where a mechanical or electrical conversion process occurs, such as a standard hydraulic motor-be it reciprocal or rotary- or some kind of direct electrical generation device. The fourth configuration of a device could be a combination of two or more of the above three configurations.

The water/oil expansion within a piston or turbine environment is the first, best application of this idea. But there are a number of other combinations of substances that could serve the same purpose as that of water/oil. This disclosure assumes coverage of all of these possible combinations. Another possible application of this idea is that of replacing oil/water as the primary fluids with a possible combination of salt/water or salt/salt fluids. One type of salt solution that could serve as the thermal carrier is a heated solution of NaCl and PbCl. But the possible combination of salts that could serve as a thermal carrier is staggeringly large. With this change of thermal carry fluid, the system could be made to operate at much higher temperatures than can be achieved with the most advanced types of oils. As for the working fluid in a salt system, water could continue to be used. But it could also be replaced with AlCl₃. AlCl₃ has a normal boiling point that approximates that of water. With this change of fluids, maximum temperatures in excess of 800° C. to 1000° C. could be obtained in this thermal to mechanical/electrical conversion system. With increased temperatures, the efficiency of the system could be made to be much greater.

Yet another possibility is to use water not as the working fluid but as the thermal carrying fluid. To achieve this later function, a low boiling point organic substances, such as isobutane, could be serve as the working fluid. This low temperature system could be used to extract energy from low grade thermal sources such as geothermal deposits or ocean thermoclines. It could also serve as back end mechanical power device for hotter run systems such as existing turbines. But water is not the only fluid that could be made to work for low temperature energy conversion systems. Other various organic compounds to also serve as possible thermal energy carriers.

Another possible arrangement of this concept is to combine two or more of the above device arrangements to create a multi-stage system that can extract energy over a very wide range of temperatures.

As stated above, the best first application of this concept would be a device running on water/oil. In this arrangement, the oil serves as the thermal carrier and the water performs the work function when mixed with the thermal carrier. Considering the staggering number of reciprocal mechanical engines in existence at the time of this patent application, the best first usage of this concept would be to modify this widely available device to operate not on chemical reactions but on liquid to gas expansion of water that is induced by heated oil provided into the system.

FIGS. 1-3 show how a converted piston engine 10 can be made to work on this concept. It will be appreciated that the figures are a simplification to allow easier description of the inventive aspects in this disclosure. For example, the engine 10 in the figures does not show the value structures used to open and close the ports responsive to piston position, but such is well known in the arts. It will also be appreciated the overall construction of a typical piston engine is well known and will not be discussed herein.

Referring now to FIG. 1, the piston 12 is undergoing a reciprocal motion and is part way up the cylinder 14 and continuing to move upwards. At this point in the cycle, the injection of thermal energy-carrying oil begins. The oil enters the cylinder cavity 17 by way of port A 19. This oil injection process continues until the piston 12 reaches its topmost position, as shown in FIG. 2. At that point, a micro injector 21 sprays a small quantity of water by means of port B 23, also seen in FIG. 2. Upon mixing in the cavity 17, the water temperature climbs rapidly, and the rate of increase in temperature greatly exceeds that of the volume increase. As such, there will be a commensurate increase in pressure. Once a high pressure is established in the cylinder/piston cavity, the piston will begin moving down against a force, As this happens, part of the thermal energy provided by the oil is converted into mechanical work. Then, when the piston nears its bottom most position in cavity 17, as shown in FIG. 3, port C 25 is uncovered and the steam/oil mixture exits the cylinder cavity 17, and the cycle begins again.

In the optimal version of this system, the exiting mixture of oil and steam is then passed through an oil/steam separator. Once separated, the oil is transferred to a heating source that brings the oil back to the temperature it was at when injected into the cylinder, then by a pumping mechanism, is returned to port A 19 of the engine shown in FIG. 1. The steam, once clear of the oil, passes through a condenser that removes heat to allow it to convert back to liquid phase. And as with the oil, the water is recycled back to the engine, again being injected into the engine by way of port B 23 at the appropriate time. In this way, this system can be made to be a closed loop, requiring only heat to be applied to the oil and heat removed from the steam to maintain the process of converting thermal energy into mechanical work.

It will be appreciated that there are numerous known processes and structures for heating the hot liquid to an appropriate temperature. For example, fossil fuels may be used to power a heater, or the liquid can be moved through a solar heater. For larger fixed engine systems, the heating source could be a coal furnace or even nuclear.

While particular preferred and alternative embodiments of the present intention have been disclosed, it will be appreciated that many various modifications and extensions of the above described technology may be implemented using the teaching of this invention. All such modifications and extensions are intended to be included within the true spirit and scope of the appended claims. 

What is claimed is:
 1. An engine, comprising: a cavity constructed to enable a working liquid to mix with a hot liquid; a first port in the cavity constructed to deliver the hot liquid into the cavity, the hot liquid delivered into the cavity at a temperature that exceeds the flashpoint of the working liquid; a second port in the cavity constructed to deliver the working liquid into the cavity, the working liquid having a flashpoint lower than the temperature of the hot liquid; a third port in the cavity constructed as an exhaust; a moving member operably coupled to the cavity and arranged to convert pressure energy in the cavity to motion energy; and wherein the hot liquid causes the working liquid to vaporize and increase the pressure in the cavity and causing the moving member to move in response to the increased pressure.
 2. The engine according to claim 1, wherein the moving member is a piston.
 3. The engine according to claim 1, wherein the moving member is a rotor.
 4. The engine according to claim 1, wherein the hot liquid is an oil.
 5. The engine according to claim 1, wherein the working liquid is water.
 6. The engine according to claim 1, further including a heater for heating the hot liquid.
 7. The engine according to claim 6, wherein the heater is solar powered.
 8. The engine according to claim 6, wherein the heater is powered by fossil fuel.
 9. A method of powering an engine, comprising: injecting a hot liquid into a cavity, the hot liquid delivered into the cavity at a temperature that exceeds the flashpoint of a working liquid; injecting a working liquid into the cavity, the working liquid having a flashpoint lower than the temperature of the hot liquid; vaporizing and expanding the working liquid on contact with the hot liquid to increase the pressure in cavity; and moving a moving member responsive to the increased pressure in the cavity.
 10. The method according to claim 9, further comprising the step of heating the hot liquid using a solar powered heater.
 11. The method according to claim 9, further comprising the step of heating the hot liquid using a fossil fuel powered heater.
 12. The method according to claim 9 where injecting the hot liquid further comprises injecting a hot oil.
 13. The method according to claim 9 where injecting the working liquid further comprises injecting water.
 14. The method according to claim 9 where moving the member further comprises moving a piston.
 15. The method according to claim 9 where moving the member further comprises moving a rotor.
 16. The method according to claim 9 wherein the molar mass of the working liquid is small compared to the molar mass of the hot liquid.
 17. The method according to claim 16, wherein the working liquid is water and the hot liquid is oil.
 18. The method according to claim 17 wherein the molar mass of the water is about 600 to 800 times less than the molar mass of the oil.
 19. The method according to claim 9 wherein the hot liquid is an oil between 200° C. and 330° C. and the working liquid is water below 100° C.
 20. The method according to claim 9 where injecting the hot liquid further comprises injecting a liquid salt. 